A 34-Year-Old Woman Suffers from Recurring Throbbing Headaches That Cause

A 34-year-old woman suffers from recurring throbbing headaches that cause significant distress. They come with nausea and photophobia. She has been to the emergency room 5 times in the last 6 months for these headaches. Her blood pressure ranges from 140/90 mm Hg to 150/95 mm Hg during office visits. The neurologic exam is unremarkable. The patient is given metoprolol and told that the medication will reduce the frequency of headaches as well as lower blood pressure in the long run. Which of the following best explains this medication's effect on blood pressure?

A) Decreased level of circulating catecholamines
B) Decreased level of circulating renin
C) Increased atrioventricular nodal conduction rate
D) Increased renal sodium and water retention
E) Long-term increase in peripheral vascular resistance